Solid-State Polymer Electrolytes Based on AB 3 -Type Miktoarm Star Copolymers.

Miktoarm star copolymers composed of three poly(ethylene oxide) (PEO) arms connected to one polystyrene (PS) chain, i.e., PS-(PEO) 3 , demonstrated synergistic improvements in the ionic conductivity and mechanical strength by factors of 2-30 compared to those shown by PS-PEO diblock copolymers. Entropic constraints for the chain stretching of (PEO) 3 gave rise to notably reduced domain sizes of PS-(PEO) 3 electrolytes, compared with the values of PS-PEO analogues. Further, the melting transition of PS-(PEO) 3 with PEO molecular weight of M n = 2 kg mol -1 was vanished with lithium salt doping at [Li]/[EO] = 0.06 under such confinements, resulting in an order of magnitude increase in the room temperature conductivity. The fact that lithium ion transport in PEO-based copolymers can be tunable by the way PEO chains are connected to hard polymers can lead to innovative designs for solid-state polymer electrolytes.